Increasing missfire RGA

[Allan R]

Got a bit of a strange one, I had a slight faulter at around 2,500 to 3,000 rpm, this has now started to worsen over the last week. On a light throttle it would faulter at these revs and then if held at 4,000 rpm again on a light throttle it would start to missfire. On a full throttle it would run fine
This has now got to the point that it still faults at at 2,500 to 3,000, but has now started to miss on full throttle at 4,000 to around 5,500 when it clears and pulls hard.
Should it be looking at timing or fueling. Assuming any of you have experienced anything like this.
Any guidance appreciated.
Al

 

[Ed Case]

This could be totally irrelevant in your case but when I had my 'Sprint' I had a Witt ignition and the bike used to 'muck' me about something terrible, misfiring, 'snatching', dying etc until I discovered that the rectifier/regulator was starting to 'break down' and was giving the control box widly fluctuating information. Advice from 'A Man Who Knows' that these R/Rs never ever fail turned out to be BS.

 

[Grant]

Plugs / gaps?
Plug caps breaking down?
HT lead to cap corrosion?
These are the sort of things that creep up over time as you describe.

 

[LaverdaIan]

Vaccuum balance hoses getting old...loose, split, collapsing...??
sometimes it's the simple things..
8)

 

[andrew112_uk]

Or an inlet manifold rubber breaking down? Do you think you are losing just one cylinder or all?

Andrew

 

[Rob]

Pick up trigger wiring partly failing.  Look for worn/brittle/broken insulation on the individual wires to the pickups.  Check the connector plug for corrosion/broken conductor.  Vibration causes the symptoms you describe on bikes that have the original pickups.

 

[Allan R]

Well after a bit of checking and cleaning carbs, wiring, timing, I eventually took the air filter out and hey presto sorted.
I found out yesterday that she ran OK cold then started to go off as she warmed up. I tried her again this afternoon and when she faltered I tried the choke and she faltered straight away, so got home and took the filter out and she ran fine.
Thanks for all your responses.
Al

 

[lemonjelly]

Al

Only just saw this,had the same when I put in a replacement oil foam soaked one hated it,went back to paper fine .

Shaun

 

[Reggie3cl]

Unifilters are utterly full of sticky oil as new and they screw up the carburation royally.  I think I gained about 20bhp on the dyno by throwing my (oiled) one out.  Remove all the oil with white spirit, dry and refit.  You're not gonna be riding a Laverda across the Sahara* so don't worry too much about filtration.

*If you do, please tell me about it!